Hello, Red fox and Complementary colors

When my elder one was 3-4 years old one of our favorite authors was Eric Carle. From his many creations are the "The very hungry caterpillar", "The mixed-up chameleon", "The very clumsy cricket", "The very lonely firefly" that we have enjoyed reading over and over again. His books are very simple, have a pattern and contain plain pictures. Kids enjoy these books and almost memorize them. They like to guess whats coming up on the next page.

Our memories were revived when I got some of his books for my little one. One of them, which we never read before, was 'Hello, Red Fox'. In a very creative and scientific way Eric Carle introduces the complementary colors and afterimage effect. Both my kids found this book amazing and we had to google to get more information. This is what we found:

Complementary colors:
There are 3 primary colors Red, Blue and Yellow. The complementary color of one of the primary color is the secondary color formed by mixing the other two primary colors. Ex: Blue and Yellow makes green which is the complementary color of Red and so on...

Afterimage Effect:
If you stare at an image of one color for 30 secs to 1 min and then look at a white surface you see the image in a complementary color. This is optical illusion and you can read more about it on wikipedia.

In the book 'Hello, Red Fox', a frog calls his friends for his birthday party and introduces them to his mom in their complementary colors, a yellow butterfly is introduced as purple butterfly etc.. His mom sees their real color but frog tells her to look at them for a while. The book has a colorful animal on left page and a blank page on the right side, you stare at the animal and then on the blank page and see the image.

For added fun with complementary colors, we downloaded the color mixing triangle worksheet and colored it.